Handling finely divided solid materials



p 0, 1968 J. J. POTTER. JR.. ET AL 3,400,985

HANDLING FINELY DIVIDED SOLID MATERIALS Filed Nov. 7, 1966 Fluldlzmg Gas Gas Source INVENTORS Jgm ILOUTTERJR. i 1

Low Erps sure United States Patent 3,400,985 HANDLING FINELY DIVTDED SOLID MATERIALS John J. Potter, Jr., and John M. Hurt, St. Albans, W. Va.,

assignors to Union Carbide Corporation, a corporation of New York Filed Nov. 7, 1966, Ser. No. 592,661 3 Claims. (Cl. 302-36) The present invention relates to an apparatus for handling of finely divided solid materials and is particularly related to an apparatus for transferring finely divided solid materials from one pressure zone to a zone of higher pressure. More particularly, this invention relates to an apparatus for transferring finely divided solid materials, in metered quantities, from one pressure zone to a zone of higher pressure in a process requiring the use of such materials.

There are numerous chemical and petroleum processes which are operated at elevated pressures and which utilize solids either as raw material or as a catalyst for the reaction. In the operation of these processes, finely divided solids must be transported from one pressure zone to a zone of higher pressure for introduction into the apparatus in which the reaction is carried out. In some instances, such as in the liquid phase hydrogenation of coal, the solid materials are blended with a suitable liquid vehicle to form a paste or a slurry which is then pumped into the high pressure zone. However, there are other instances such as in the carbonization of coal which require handling of the coal in the dry state. It therefore becomes necessary to transport the coal, preferably in finely divided form, from storage (zone of lower pressure) to a zone of higher pressure.

Various systems have heretofore been employed for such purpose as, for example, star feeders, multiple high pressure lock hoppers or blow cases and other comparable mechanical means. However, these systems have been uneconomical and have otherwise undersirable characteristics, such as a tendency to pack the finely divided solids so as to cause injection into the reaction zone in lump form, or to require excessive amounts of fluidizing gases, as when lock hoppers or blow cases are employed. Star feeders, on the other hand can be used only with limited pressure differential across the rotor sealing edges and they are subject to rapid wear of the sliding surfaces.

US. 2,667,280 discloses a pump-type apparatus which partially eliminates the foregoing problems. However, there are several disadvantages associated with the apparatus described in said patent. For example, the lack of a positive seal which separates the solids from the stutfing box fails to prevent the erosive etfect of the solids on the packing. Furthermore, the method of distribution of the fluidizing gas into the pump chamber must be carefully designed in order to attain adequate fluidization of the solids in the chamber.

Accordingly, it is an object of this invention to provide a pump-type apparatus for the transfer of finely divided solids from one pressure zone to a zone of higher pressure. It is a further object of this invention to provide such an apparatus which is free from the aforementioned limitations existing in the prior art systems. It is still another object of this invention to provide a pump-type apparatus for transferring finely divided solids, in metered amounts, with the use of a minimum quantity of fluidizing gas, without compacting the solids and with minimum or no abrasive effects upon the mechanical components of the pump.

The invention and its objects will be more clearly understood from the following description taken in conjunction with the accompanying drawing in which a representative form of the apparatus is illustrated schematically and partly in vertical section.

Referring now specifically to the drawing, the numeral 1 designates a cylindrical body or pump cylinder fitted with a cylindrical member 3 (hereafter plunger member 3) with which it defines an annular space 5. Plunger member 3 is connected to a drive means 7 through a coupling member 9 or by some other suitable means. A pair of oppositely located spherical machined surfaces 11 in the coupling member 9 provide ,a floating-head type of connection between the plunger member and the drive means. Machined surfaces 11 are ordinarily engaged during the discharge stroke of the pump in order to permit exact alignment of the plunger member within the pump cylinder independent of the alignment of the pump cylinder with drive means 7.

Although a floating-head type of connection is shown in this drawing, there are of course other suitable means and methods of connection which are obvious to those skilled in the art. Furthermore, drive means 7 can be activated by a steam cylinder, hydraulic cylinder, a crank connection or any other suitable means (not shown in the drawing) in order to impart a reciprocal motion to the plunger member 3 along its principal axis.

Stuffing box 13 provides a gas-tight seal between the lower end of the pump cylinder and the plunger member. Stuffing box 13 which contains conventional packing materials is held securely in position by latern ring and follower members 15 and 17 respectively situated on both sides of the stufiing box and by a retainer ring 19. Follower 17 is ordinarily a closely fitted bushing or any other similar member whereas latern ring member 15 is a combination bushing and a distributing ring or a diffuser which is also employed for the distribution of the fluidizing gas as will hereinafter be explained. The stulfing box, the follower members and the retainer ring prevent leakage of the gas and insure alignment of the plunger member within the pump cylinder.

Alignment of the plunger member 3 within the pump cylinder at the top end of the apparatus is secured by a bearing member 21 which is fitted closely Over the plunger member and adapted to slide thereover. Piston rings 23 placed on both sides of the bearing member and held securely in position by a retaining member 25 provide a gas-tight seal at the top end of the apparatus.

The packing (in stufiing box 13), the follower members 15 and 17, retaining ring 19, hearing member 21, piston rings 23 and, in general, all the pressure sealing elements are selected from elastomeric materials such as Teflon, neoprene, rubber, etc., whenever the temperature to which they are subjected is up to about 500 F. At higher temperatures, however, other materials of con struction such as metals (e.g., brass, aluminum, cast iron, etc.), graphite, asbestos, etc., are more suitable than the elastomers.

Also shown in the drawing are conduit 27 connected to the fluidizing gas source (not shown), a valve 29, pressure reading means 31 such as a pressure gauge, and conduit 33 which terminates in the annular space 5 adjacently below follower 15. Passage means 35 in the upper end of the apparatus provides communication between the annular space 5 and a plenum chamber 37 machined in the upper surface of the retaining member 25. A perforated member 39 such as a screen, grid, sintered metal disk, etc., shown at the top of retaining member 25 provides for the passage of the fluidizing gas into the clearance pocket of the pump chamber. The pump chamber is defined by the space within pump cylinder 1 between the positions indicated by the lines AA and AA which correspond to the end of the discharge stroke and the end of the suction stroke of the plunger member respectively. Thus when the pump is at the end of its suction stroke, the plunger member is retracted to the position indicated by AA and when the pump is at the end of its discharge stroke the upper end of the plunger assumes the position indicated by AA.

The solid materials are contained within storage vessel 41 which can be a bin, a hopper or a standpip-e, and wherein the solids are slightly fluidized to facilitate their withdrawal through solid discharge line 43, valve 45 and solids feed line 47 which communicates with clearance pocket 50 above the perforated member 39. Valve 45 opens and closes to permit the introduction or stoppage of the solids flow from the storage vessel into the pump chamber. A gas-tight seal between solids feed line 47 and pump chamber is provided by a suitable gasket 49 which can be an elastomer, metal, graphite, asbestos, etc.

At the top, the pump cylinder 1 is closed by closure means 51 and O-ring seal 53. Passage means 55 extends centrally through closure means 51 and provides communication between the pump chamber and valved conduit 59 having a valve 57. Extending laterally from passage means 55 is a second passage means 61 having a valve '63 as shown in the drawing. The entire assembly shown in the drawing is supported by a supporting member such as a flange 65.

In operation, when the plunger member 3 reaches the end of its discharge stroke, valves 29 and 57 close simultaneously thus interrupting the flow of the fluidizing gas through conduits 33 and also seal the pump discharge line 59 which communicates with the desired system to which the solids must be pumped. The valves shown in the apparatus of this invention are generally ball valves, although other suitable valves can also be employed. These valves can be pneumatically, electrically or mechanically activated and are operated in a controlled and proper sequence as it will become apparent hereinafter.

As the plunger member is retracted, valve 63 opens to vent the gas which has remained in the clearance spaces within the pump and also to reduce the pressure in the pump chamber to atmospheric level. Valve 63 can remain open or closed until the discharge cycle. If it is closed, the retraction of the piston from the pump chamber creates a vacuum therein which aids in charging the solids from the storage vessel into the pump chamber. Valve 45 is then opened to permit the flow of solids from storage vessel 41 through solid feed line 47 into the pump chamber. When the plunger member reaches the bottom end of its stroke, valve 45 is closed and valve 63, if not previously closed, will also be closed. Valves 29 Will open to admit the fluidizing gas through conduit 27 and through latern ring 15 (diffuser), annular space 5, passage means 35 and perforated member 39 into the pump chamber to fiuidize the solids therein. The fluidizing gas can be nitrogen or the very gas which is employed in the high pressure zone to which it is desired to transfer the solid materials. Since the solids must be fluidized within the pump chamber, it is of course desirable to employ the solids in finely divided form to facilitate their fluidization. Furthermore, the fluidizing gas is admitted into the pump chamber until the pressure therein is as high as or is slightly above the pressure in the system to which the solids are being transferred. When the pressure in the pumping chamber reaches the desired level, valve 29 is closed (valve 45 is also already closed) and valve 57 is opened to permit passage of the fluidized solids through line 59 into the desired system and the cycle is then repeated until the desired amount of solids are transferred.

The amount of fluidizing solids which is transferred from the storage vessel 41 to the zone of higher pressure can be controlled and regulated by judicious selection of the amount of solid fed to the pumping chamber and the quantity of fluidizing gas which is admitted therein. It is thus possible to transfer the solids in metered and 4 predetermined quantities which is often necessary for the successful operation of many processes.

The pump-type apparatus which has heretofore been described is capable of pumping finely divided solids from one pressure zone, say, atmospheric, to a zone of higher pressure of the order of about 10,000 p.s.i.g. or even higher. The provision of a plunger member in the manner illustrated by the drawing prevents the solids from entering into the stufling box. Therefore, the packing is exposed to the fluidizing gas only and the erosive effects of the solids are virtually eliminated. Also, the distribution of the fluidizing gas in the manner which was previously described results in good fluidization of the solid particles without compacting. This of course is essential to successful and efficient operation of an apparatus of this type.

Although the present invention has heretofore been described with a certain degree of particularity, it should be understood that many modifications and revisions can be made both in the construction of the apparatus and its method of operation which are nevertheless suggested from the present description and which therefore fall within the spirit and scope of this invention.

What is claimed is:

1. An apparatus for transferring solid materials from one pressure zone to a zone of higher pressure comprising, in combination, a cylindrical body with an upper end and a lower end and having a chamber therein, a cylindrical body member coaxially disposed within said cylindrical body so as to define an annular space therewith, means for providing a seal between the lower end of said cylindrical body and said cylindrical member, drive means connected to the lower end of said cylindrical member and adapted to impart reciprocal motion thereto between a first position and a second position, said first position being the end of the discharge stroke and said second position being the end of the suction stroke of said cylindrical member, said chamber in said cylindrical body being defined between said first position and said second position, means for providing a seal between the upper end of said cylindrical member and said cylindrical body, a gas inlet means at the lower end of said cylindrical body communicating with said annular space, a perforated plate member disposed in the upper end of said cylindrical member, a closure means sealably disposed at the upper end of said cylindrical body, a first passage means extending centrally within said closure means and communicating with said chamber, means for introducing solids into said chamber and passage means for providing communication between said annular space and said chamber.

2. The apparatus as claimed in claim 1 in combination with a diffuser member disposed adjacently above said gas inlet means to thereby distribute the gas through said annular space.

3. The apparatus as claimed in claim 1 wherein said gas inlet means, said solid inlet means and said first passage means all contain valve means automatically responsive to the movement of said drive means such that said solid inlet means is open when said cylindrical member moves from said first position toward said second position while said gas inlet means and said first passage means are closed, and wherein said solid inlet means is closed during movement of said cylindrical member from said second position toward said first position while said gas inlet means and said first passage means are in the open position.

References Cited UNITED STATES PATENTS 1,595,362 8/1926 Schaefer 30236 X 1,609,401 12/1926 Crites et al 30238 2,395,727 2/1946 Devol 302-29 X 2,667,280 1/1954 Lane et al 214l52 ANDRES H. NIELSEN, Primary Examiner. 

1. AN APPARATUS FOR TRANSFERRING SOLID MATERIALS FROM ONE PRESSURE ZONE TO A ZONE OF HIGHER PRESSURE COMPRISING, IN COMBINATION, A CYLINDRICAL BODY WITH AN UPPER END AND A LOWER END AND HAVING A CHAMBER THEREIN, A CYLINDRICAL BODY MEMBER COAXIALLY DISPOSED WITHIN SAID CYLINDRICAL BODY SO AS TO DEFINE AN ANNULAR SPACE THEREWITH, MEANS FOR PROVIDING A SEAL BETWEEN THE LOWER END OF SAID CYLINDRICAL BODY AND SAID CYLINDRICAL MEMBER, DRIVE MENS CONNECTED TO THE LOWER END OF SAID CYLINDRICAL MEMBER AND ADAPTED TO IMPART RECIPROCAL MOTION THERETO BETWEEN A FIRST POSITION AND A SECOND POSITION, SAID FIRST POSITION BEING THE END OF THE DISCHARGE STROKE AND SAID SECOND POSITION BEING THE END OF THE SUCTION STROKE OF SAID CYLINDRICAL MEMBER, SAID CHAMBER IN SAID CYLINDRICAL BODY BEING DEFINED BETWEEN, SAID FIRST POSITION AND SAID SECOND POSITION, MEANS FOR PROVIDING A SEAL BETWEEN THE UPPER END OF SAID CYLINDRICAL MEMBER AND SAID CYLINDRICAL BODY, A GAS INLET MEANS AT THE LOWER END OF SAID CYLINDRICAL BODY COMMUNICATING WITH SAID ANNULAR SPACE, A PERFORATED PLATE MEMBER DISPOSED IN THE UPPER END OF SAID CYLINDRICAL MEMBER, A CLOSURE MEANS SEALABLY DISPOSED AT THE UPPER END OF SAID CYLINDRICAL BODY, A FIRST PASSAGE MEANS EXTENDING CENTRALLY WITHIN SAID CLOSURE MEANS AND COMMUNICATING WITH SAID CHAMBER, MEANS FOR INTRODUCING SOLIDS INTO SAID CHAMBER AND PASSAGE MEANS FOR PROVIDING COMMUNICATION BETWEEN SAID ANNULAR SPACE AND SAID CHAMBER. 